#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<assert.h>
char* my_strcat(char* p2, char* p1)
{
	assert(p1);
	assert(p2);
	char* m = p2;
	while (*p2 != '\0')
	{
		p2++;
	}
	while (*p2++ = *p1++)
	{
		;
	}
	return m;
}
int main()
{
	char arr1[] = "world";
	char arr2[20] = "hello ";
	char* ret = my_strcat(arr2, arr1);
	printf("%s\n", ret);
	return 0;
}